\(A=\{1,2,3,4,5,6,7,8,9\}\) के कितने (5)-तत्व उपसमुच्चय (2) और (3) दोनों को साथ शामिल नहीं करते?
How many (5)-element subsets of \(A=\{1,2,3,4,5,6,7,8,9\}\) do not contain both (2) and (3) together?
Explanation opens after your attempt
Correct Answer
A. (91)
Concept
Total subsets are \(\binom{9}{5}=126\) and those containing both (2), (3) are \(\binom{7}{3}=35\). Hence (126-35=91).
Why this answer is correct
The correct answer is A. (91). Total subsets are \(\binom{9}{5}=126\) and those containing both (2), (3) are \(\binom{7}{3}=35\). Hence (126-35=91).
Exam Tip
कुल \(\binom{9}{5}=126\) हैं और (2), (3) दोनों हों तो \(\binom{7}{3}=35\) हैं। इसलिए (126-35=91) है।
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